A 34-year-old man remains in custody this morning as part of an investigation into cyber fraud by international crime gangs.
It follows the removal of money from customer accounts and damage to a number of ATMs.
Gardaí say the operation - which involves UK Police and Europol - is still ongoing.
The man, who is a Romanian national, was arrested yesterday in Dublin city as part of an operation by detectives from the GNECB - The Garda National Economic Crime Bureau - working closely with police across Europe.
It followed a report by a bank on January 13th, one of several incidents of ATM transaction reversal fraud earlier in the month.
It appears 18 ATM machines were targeted in the capital between the 8th and the 10th of January, leading to the theft of money from accounts and damage to ATMs.
The man detained is being questioned at Store Street Garda Station where he can be held for up to seven days.
